Dc

The intercept on the t axis is the diffusion lag time tL, which is given by h2

The second "initial condition," however, is for a system that has been stored for some time, and the drug saturates the entire membrane. Mathematically, there is a nonzero uniform initial drug concentration C0 distribution within the membrane. Similarly, Fick's second law (Eq. 4.2) can be solved with the following boundary and initial conditions: